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02 Sensors

New 03/05/2005, UD 03/12/2005

I recently solved (or had solved for me!) a long standing problem with
my 98. Car idled poorly at times, and had a bit of a miss at times when
not accelerating. Threw both lean and rich codes for bank one. I had
previously had the bank one upstream o2 sensor replaced, ordered the
part myself from Rock auto. Got the motorcraft. My mechanic finally
gave up on the problem, and I was referred to a guy here in St. Louis
who specializes in diagnosing problem cars. Took him about an hour to
figure out that the motor craft part was causing a problem, and not
working properly. He told me he found this to be the case often in
"special use" fords, the after market parts for emissions and ignition
don't work right in some cases. He recommended sticking with the ford
parts for o2 sensors and other emissions systems. Of course he sees a
lot of problem cars, so I don't know how prevalent this is, but I
thought some on the list might find this helpful.
I spent a lot of time trying to track this issue down, and to have it be
something dumb like this.....

Patrick Nabors
Glad to hear you got your problem figured out. Your mechanic is correct
that aftermarket parts are, sometimes, inferior to OEM parts. The
Motorcraft part you bought is exactly the same part that you would buy from
Ford. You just got a bad one. Many OEM Ford parts - spark plugs, wires,
coils, switches, sensors, motors, fuel pumps - are Motorcraft parts. They
come in a Motorcraft box even when you buy them from the Ford dealer.

Glen Murdock
On my '93 the OEM Ford O2 sensors also had NGK stamped on them.
Hi Glen, you may be right, but in this case, there is a visible
difference in the parts, as opposed to the coil on plugs which didn't
look any different from what I had on the car. In this case the plastic
clip area was black instead of being blue, or green, I cant remember
which bank is which color. Anyway, whatever the case, glad to have it

Patrick Nabors
Hi Larry, in the interest of full disclosure and a more complete picture of this problem, I have a few things Iíd like to add. (Since you are putting this on the site, I felt it was important to have all the information out there!)

I had a series of minor issues with this car, after I bought it. I had never run right, and the SES light had been on more than once. The last part that was diagnosed as definitely bad was the O2 sensor for upstream bank one. This still didnít fix the miss I was experiencing, and any time the car was hooked up to a scanner, the fuel trim ran up and down. I had just been living with the problem, but asking around to try to figure out what could be wrong with it. One day I got the bright idea to call Doug Lewis at Ford Performance in Atlanta. Doug told me that he had run into a similar issue with a clients car, which had turned out to be switched wires between upstream bank one, and downstream bank two. Apparently the two are right next to each other. I haven't been under the car my self, but apparently this is a pretty easy mistake to make, or at least it happens occasionally. (you may want to verify that I have this right, as I donít want to misquote Doug, but these are the wires that were switched on my car)

Anyway, I relayed this to my mechanic, but when we swapped the wires, it didnít fix the problem. However when the shop that did the diagnostic work on the car looked at it, they found that the wires were switched, but the faulty O2 sensor was in there as well. So I am not sure what the primary cause of the problem was, but fixing both issues was what it took to get the car running properly.

I am glad to hear you are able to use this info on the site, and want to say thanks to Doug Lewis, and Brian King, as well as a few others who tried to help in diagnosing the problem.

Thanks Larry!

Patrick Nabors


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